First make sure that your markup is valid. E.g. for your li tags the ul tag was missing.

If you want to display 4 divs, you need the class col-md-3 instead of col-md-4. Bootstrap is using a grid system with a default column count of 12. If you need 4 columns you have to use 12/4 = 3 meanding col-md-3.

The md stands for medium. So for small devices, the columns break and are displayed on top of each other. Watch the following example in fullscreen, to see the columns standing next to each other.